The invention relates to an improvement in or relating to the end clamping members of a magnetic core of a power transformer having a horizontal and preferably cross-section magnetic circuit, the ends of the clamping members bearing on the wall of the transformer tank.
The invention relates more particularly to a shell type transformer in a form-fit tank. The magnetic circuit of such a transformer is horizontal and the tank is in two parts--a bottom part or base having a flange serving as end member for the yokes of the magnetic circuit, and a top part or dome which serves to clamp the yokes. The magnetic core, which is usually vertically divided into two equal parts by a cooling channel, is borne by a T-beam bearing at its ends on the flanges of the base, the vertical "stroke" of the T being positioned at the bottom of the channel. Magnetic shunts are welded below the horizontal web or "dash" of the T-beam, the shunts usually being welded on edge and serving to channel leakage flux. The magnetic shunts welded along each edge of the said web--i.e., the magnetic shunts near the edges of the magnetic core--are the ones which are the most heavily saturated by the leakage flux and therefore the ones determining how high the magnetic shunts must be. As a rule, the end clamping member for the top of the magnetic core is constructed symmetrically in respect of the end clamping member for the bottom of the magnetic core as just described except that the T-beam has no "stroke". The disadvantages of such a system are that some of the magnetic shunts are needlessly high, while the "stroke" of the T-beam either impedes the flow of oil in the central channel of the core or requires the presence of such a channel in cases where there is no other reason for providing a channel.